Drill



A. L. HAWKESWORTH.

DRILL.

APPLICATION FILED MAR.2I, I9I9.

L38U 554v Patented June 7, 1921.

v Arz/wL-jm/marm- 4 ATTORNEY.

ARTHUR L. HAWKESWORTH, 0F BUTTE, MONTANA.

. DRILL.

, Specification of Letters Patent.

Patented June "3, 1921i.

Application fi1ed Mar'ch 21, 1919. Serial No. 283,954.

tion being to provide means for effectively locking the bit to the shankof the drill and yet permit of its ready removal when the occasionarises to detach the bit for purposes of sharpening the same, orreplacing a worn out bit with a new one. The advantages of the improvedconstruction will be fully apparent from the following detaileddescription in connection with the accompanying drawings in which--Figure 1 represents an elevation of a drill turned so as to present thewide ends of the central interlocking tongue and groove of the bit andshank respectively; Fig. 2 is a side elevation of the drill; Fig. 3 isan eleva tion of the bit detached and turned to present the narrow endof its tongue; Fig. 4.- is an elevation of the shank turned to presentthe narrow end of its groove; Fig. 5 is a bottom plan of the bit; andFig. 6 is an end view of the shank showing in plan the severalformations cooperating with the formations on the bottom of the bit.

Referring to the drawings, 1, represents a a drill-bar or shank providedwith an axial pasage-way or duct (4 for the circulation of water usuallyemployed in drilling operations as well understood in the art. The shankterminates at one end (the end opposite that from which the same isoperated) in a tapering transverse groove 2 disposed across the axis ofthe shank, the groove being of uniform depth and being disposed on adiagonal or at an incline to the axis (longitudinal) of the shank. Theend faces h, h, of the shank on either side of the groove are disposedin the same plane, said plane being parallel with the plane of thebottom of the groove. The taper of the side or bounding walls of thegroove is in a direction away from the cutting end of the drill for areason to presently appear. Leading from the sides of the groove 2 arerecesses 3, 3, of

uniform and equal depth, the bottoms of the recesses under thecircumstances being necessarily parallel to the conver ing side walls-ofthe groove from which t ey lead. The bit 4 is formed or provided with atongue 5 snugly fitting the groove 2, said tongue being provided withside ribs 6, 6, cooperating wtih the recesses 3, 3. To attach the bit tothe shank, thetongue 5 is inserted with its narrow end into the wide endof the groove 2, the ribs 6, 6, at the same time being received by therecesses 3, 3. By then moving the bit across the shank the full llmit oruntil further movement is arrested .by the converging walls of thegroove, the

bit will be in proper working position. WVhen in position the duct awith which the bit is provided will be in alinement with the duct a ofthe shank so that the water is free to flow'to the surface beingdrilled.

The taper of the groove 2 (and necessarily that of the tongue 5) beingaway from the cutting end 'of the drill, it follows that when the bit isonce attached and the drill operated, the axial pressure or blowsimparted to the shank to carry on the drilling" I.

will tend to drive the shank up the incline of the top face t of' thetongue, or what amounts to the same thing, to' drive the bit down theincline of the bottom of the groove 2, this action having the effect oftightening the bit on the shank instead of loosening the same, the bitbeing all the time forced toward the narrow end of the groove 2. At thesame time the interlocking action between the members 3 and 6 serves toprevent displacement of the bit in the line of the axis of the shank. Todetach the bit a slight tap delivered against the same at the narrow endof the groove 2 will force the bit across the shank axis toward the wideend of the groove as indicated by the arrow I in Fig. 2, therebypermitting ready withdrawal of the bit. While in the present embodimentof my invention I show the tongue 5 disposed on the bit and the groove 2and recesses 3 on the shank, it would be fully within the spirit of myinvention to reverse the positions of the members, forming-thetongue onthe shank and the groove with its'recesses on the bit, Thecross-sections of the groove and recesses may obviously be varied, myinvention in no wise restricting me to the forms here shown. In thepresent embodiment of the invention, when the parts are assembled, thefaces of the ofisets e, e, on

[all

- either side of the tongue rest against the faces h, k, on either sideof the groove 2, the top face at of the tongue bearing against'thebottom of the groove. In the form here shown the lateral recesses 3 aredisposed in a common plane transverse to the axis of the drill,necessitating a like disposition for the ribs 6; but it is obvious thatI am not to be limited to this precise arrangement for these parts.stricted to ribs 6 made continuous as here shown, any equivalentsthereof coming within the scope of the invention. The tool may in factbe changed in many particulars without involving a departure from thebasic principle of the invention.

Having 'described my invention What I claim, is: I

I. In combination with a drill-bar or shank, a bit movable across theshank, taper= in transverse groove disposed across the axis of the drilland at an incline to said axis being formed on one of the members, theend faces of the memberon either side of the groove being parallel tothe bottom of the groove, a corresponding tapering tongue and boundingoffsets therefor-being formed on the opposite member andinterlocking'with the formations on the first member, the direction ofthe taper of the groove and tongue aforesaid relatively to the cuttingend of.

the drill being such as to cause the bit to tighten on the shank duringthe drilling operation, suitable recesses having parallel side wallsleading from the groove aforesaid, and formations on the opposite memberengaging said recesses, whereby the bit is positively secured-to theshank.

2. In combination with a drill-bar or shank, a bit movable across theaxis of the shank, a tapering transverse groove dis- Neither do I wishto be rerestate posed across the axis of the drill and at an incline tosaid axis being formed on one of the members, the end faces of themember on either side of the groove being parallel to the bottom of theroove, a corresponding tapering tongue and bounding offsets thereforbeing for-med on the opposite member and interlocking with the formationon the first member, the direction of the taper of the tongue and grooveaforesaid relatively to thecutting end of the drill .being such as tocause the bit to tighten on the shank in the drilling operation,recesses having parallel side walls leading from the sides of thegrooves aforesaid, and suitable formations on the tongue for enteringsaid recesses and positively securing the bit to the shank. I 3.- Incombination with a drill-bar or shank, a bit movable across the shank, atransverse groove disposed across the axis of the shank at an incline tosaid axis and tapering on the sides in a general direction from thecutting end of the drill, lateral recesses having parallel side wallsleading from the groove in a direction transverse to the axis of theshank, the faces of the

